As the world heats up, many animals will need to move to find a suitable climate. But some may struggle to keep up with the pace of change.

While at Sapienza University of Rome, researcher Luca Santini began studying how mammals will adapt. He looked at the biological traits that affect how quickly species can colonize new areas – for example, their rate of population growth and if they can move long distances.

Santini: “What we found was that around 30 percent of species on average are predicted to be slower than climate velocity. This means that they’re probably going to lose part of their range, and so reduce their population size … and so increase their probability of extinction.”

The idea of losing 30 percent of species is a sobering one – and Santini says it’s likely a best-case scenario. His estimate does not take into account other factors that can prevent at-risk species from moving to more suitable areas.